To throw a bachelorette/bachelor party on The Sims 3 (Generations EP), you'll need to have two sims engaged. while on the sim, click the phone and choose "Throw party" or "Throw party at..." (if you want it held somewhere else in town). Under the options, click Bachelorette/Bachelor Party and choose the time. The only dress code option is "Dress to impress" so simply choose that. Invite guests (mainly girls/men your sims' age).
edit; i totally just answered a whole different question..
but you cant actually 'hire' strippers. They may show up themselves after about two hours, or if you invite a good friend they may bring someone 'special'. Even just inviting normal guests, apparently they may bring a stripper but most likely they come on their own. Like in the generations trailer.
Chat with our AI personalities
Yes you can hire a babysitter. You do this by calling for services and selecting "Babysitter".
Generations
The Sims 3 is the base game for the whole Sims 3 franchise. To play the Sims 3 Generations, you must have the base game. Sims 3 Generations is an expansion pack which includes things like new hair, clothing, and furnishing. You are also able to record home movies as a Sim, take afterschool classes (ballet and scouting) as a child, and do tons more. The Sims 3 Generations makes things like prom and graduation available for teen Sims. Sims 3 Generations focuses a great deal on the teen and children section of Sims lives.
in buy mode
Lots are out. The sims 3 university, sims 3 nightlife, sims 3 adventures, sims 3 generations... you name it!